A rare airmail stamp that would have been worth as much as $200,000 if uncancelled was used to mail in an absentee ballot in Florida. Now it's worth only $20,000 to $100,000 and belongs to the government and has to remain sealed in a ballot box for 22 months. Here's a link to the story:

http://www.usatoday.com/news/nation/2006-11-11-inverted-jenny_x.htm